JP3951979B2 - Hull shape - Google Patents

Description

  The present invention relates to a hull shape of a medium / small boat.

  The resistance that the hull receives during navigation is mainly caused by frictional resistance caused by friction between the hull surface and water in the water, and when the ship moves forward, water hits the bow and creates energy. There is a wave-making resistance that works as a resistance. In general, friction resistance is generated in water and wave resistance is generated near the draft surface. These resistances are analyzed using hydrodynamics, and the rate of increase in wave resistance is higher than the rate of increase in friction resistance as the traveling speed increases. Is supposed to be bigger. For example, it is said that wave resistance is about 10% of resistance received by large tankers with slow traveling speed, and that the ratio of wave resistance reaches 50% in medium and small high-speed ships. As the resistance to the hull increases, the energy required to move the ship naturally increases, so reducing frictional resistance in large ships and reducing wave-making resistance in medium and small ships is an important issue. It was.

  Conventionally, as a method of suppressing the frictional resistance and the wave-forming resistance, a method of making the hull surface in contact with water at the bow portion a smooth and low-resistance shape, and a wave formed during advancing by providing a projection on the bow portion and this projection There are known methods for mainly improving the bow portion, such as making the waves near the bow smaller by causing them to interfere with each other.

  However, the method of adding improvements to these bow parts can be applied when the speed is relatively slow as in large ships and the bow part is always submerged in water. In the case of traveling in a planing state (a state where the bow portion is lifted and protrudes from the water) as shown in FIG. 10 such as when the speed is high, even if the bow portion is improved, the draft surface moves backward. There was a problem that the effect of reducing resistance could not be expected so much.

In addition, in the conventional method of improving the bow part, the wave is caused by the impact of the wave when the ship is pitched, the impact of the wave hitting the bottom of the ship when the bow is lifted, or by bad weather as shown in FIG. There is also a problem that the ride is very uncomfortable because the ship's bottom receives a large impact when the bow rises extremely against the surface of the water when it is quite high and falls back into the waves (slamming). Furthermore, when navigating in the above-mentioned planing and slamming states, the ship is decelerated when the bow is lifted and is accelerated again when the bow is lowered in order to avoid wave shock and maintain the balance of the hull. There is also a problem that the progress energy is greatly lost and the fuel consumption is lowered because it is necessary.
JP-A-7-329874 Japanese Utility Model Publication No. 6-42580

  Therefore, the present invention is a hull shape that improves the riding comfort by reducing the resistance to the hull during navigation in small and medium sized vessels, thereby increasing the navigation efficiency and reducing the fuel consumption, and at the same time suppressing the impact due to pitching and slamming. It is an issue to provide.

The hull shape of the present invention is a hull shape of a medium or small ship, and a second bow is provided behind the bow to reduce wave resistance to the sailing hull. A concave curved surface is formed in a portion from the outer plate to the vicinity of the center line of the bottom vessel outer plate, and the bottom outer plate width is narrow in the concave curved surface forming portion, and the second bow is It shall be provided between 15% and 50% from the tip with respect to the full length.

(Invention of Claim 2)
The hull shape of the present invention is the hull shape according to claim 1, wherein the second bow is formed from the vicinity of the upper edges of the left and right lower ship side skins.

(Invention of Claim 3)
The hull shape of the present invention is the hull shape according to claim 1, wherein the second bow is provided between 15% and 30% from the tip with respect to the full length of the ship.

(Invention of Claim 4)
The hull shape of the present invention is the hull shape according to claim 1, wherein the concave curved surface forming portion has a shallow mortar shape.
(Invention of Claim 5)
The hull shape of the present invention is such that, in the hull shape according to claim 1, the bottom plate width is narrow so that the concave curved surface forming portion has a substantially V-shaped cross section.

  From the contents described in the column of the best mode for carrying out the invention shown below, by reducing the resistance to the hull during navigation in small and medium sized ships, the navigation efficiency is increased and the fuel consumption is suppressed. Riding comfort could be improved by reducing the impact of slamming.

  The hull shape of the embodiment of the present invention will be described below.

  FIG. 1 is a perspective view from the bottom of a hull of a ship (S1) according to an embodiment of the present invention.

  In this hull, reference numeral 1 is a bow, reference numeral 2 is a second bow, 3 is a projecting bow, 4 is a ship side skin (40 is a lower ship side skin, 41 is an upper ship side skin), 5 is a ship bottom skin, and 6 is a keel. , 7 indicates the stern. The bow 1 has a pointed shape for the purpose of reducing wave resistance. However, since the wave-making resistance cannot be sufficiently suppressed by just sharpening the bow 1, a protruding bow 3 is provided at the lower part of the bow 1, and a wave generated by hitting the bow 1 and a wave generated by hitting the protruding bow 3 The wave-making resistance is further reduced by causing the two to interfere with each other. The hull side surface is formed by a ship side skin 4 composed of a lower ship side skin 40 and an upper ship side skin 41 from the back of the bow 1 to the stern 7. Further, a keel 6 called a ship spine extends from the rear of the projecting bow 3 to the stern 7 in the center of the bottom shell outer plate 5. In FIG. 1, the embodiment of the present invention is not directly related to the cabin portion located in the upper part of the hull, the screws provided in the vicinity of the stern 7, and the like are omitted.

  In the present embodiment, a second bow 2 is provided immediately behind the bow 1, and the second bow 2 extends from the vicinity of the boundary line between the lower ship side outer plate 40 and the upper ship side outer plate 41 from the bottom bottom plate. 5 is formed by forming a concave curved surface in a portion up to the vicinity of the keel 6. That is, as shown in FIG. 2, the concave curved surface of the second bow 2 has a shallow mortar shape that gradually increases in depth as it proceeds in the direction of the arrow, and as shown in FIG. As in the bow 1, the cross section is substantially V-shaped from the upper end of the lower ship side outer plate 40 to the ship bottom outer plate 5. Therefore, as shown in FIG. 4, the width W <b> 2 of the bottom shell plate 5 in the concave curved surface forming portion is narrower than the width W <b> 1 in the other portion of the bottom plate 5.

  Since the hull shape of the present invention is as described above, navigation is performed in a state where the bow 1 protrudes from the water surface and the draft surface moves backward in the planing state as shown in FIG. At the same time, the second bow 2 functions to suppress the wave-forming resistance in the same manner as the bow 1. In other words, the pressure at the time of the wave collision is reduced by the presence of the second bow 2 like the bow 1 that is sharpened to reduce the pressure when the wave hits, and if the pressure is reduced, the wave is reduced. Energy to make becomes small. Therefore, since resistance is reduced, navigation efficiency is increased and fuel consumption can be suppressed. Further, if the wave resistance is reduced, no wave is formed, or even if it is made, since it is a relatively small wave, pitching can be suppressed.

  Further, since the water flowing into the concave curved surface portion of the second bow 2 is held so as to wrap the ship, the lift is increased to push up the entire ship, and the balance is improved to suppress left and right shaking.

  Further, as described above, since the width W2 of the bottom shell 5 of the second bow 2 is narrow, the impact on the hull during slamming as shown in FIG. Since it is suppressed from the impact received when the vehicle is wide, the ride comfort can be improved. This is because the bottom shell 5 having a concave curved surface of the second bow 2 having a substantially V-shaped cross section as shown in FIG. This is because the action of cutting the water works more effectively, so that the water can be smoothly landed. Therefore, in order to keep the balance of the hull by avoiding wave impacts when navigating in the planing state and slamming state as in the past, the ship is decelerated when the bow part is lifted, or accelerated again when the bow is lowered, etc. Since it is not necessary to repeat the maneuvering, it is possible to further reduce fuel consumption.

  Similarly, when the bow 1 is lifted, the impact of the waves flowing toward the ship and hitting the ship bottom skin 5 can be suppressed, so that the riding comfort can be further improved.

  Further, as shown in FIG. 7, when navigating in a state where a part of the bow 1 is submerged in the water without planing, the wave (first water flow M 1) and the Waves created by the two bows (second water flow M2) cancel each other, so that wave formation is suppressed and wave-making resistance is reduced. Furthermore, in the combined water flow of the first water flow M1 and the second water flow M2, bubbles are generated by the impact when the first water flow M1 and the second water flow M2 cancel each other, and these bubbles are formed between the ship side skin 4 and the hull inundated layer. Friction resistance is also reduced because it goes in between. Similarly, as shown in FIG. 8, the first water flow M1 and the second water flow M2 cancel each other and suppress the wave-making resistance, and bubbles generated by the composite water flow diffuse along the ship bottom outer plate 5 on the ship bottom. Because it flows to the stern, frictional resistance at the bottom can be reduced.

  In this embodiment, it is a ship which has the keel 6 in the center of the ship bottom outer plate 5, but it is not restricted to this, The ship which the keel 6 is not provided may be sufficient. Similarly, although the protruding bow 3 is provided in the lower part of the bow 1 in this embodiment, the ship without the protruding bow 3 may be sufficient. Further, in the present embodiment, the second bow 2 is formed from the vicinity of the boundary line between the lower ship side outer plate 40 and the upper ship side outer plate 41, but the upper end of the upper ship side outer plate 41 and the center of the lower ship side outer plate 40. It may be formed from the vicinity of the part. Further, in the present embodiment, the concave curved surface of the second bow 2 has a shallow mortar shape. However, as shown in FIG. 9, the depth gradually increases as it proceeds in the direction of the arrow with respect to the longitudinal direction of the ship. Such a shape may be used. Further, in the present embodiment, the second bow 2 is provided in a mode that is continuous immediately behind the bow 1. Specifically, the second bow 2 is 15% to 50% (preferably 15%) from the tip with respect to the entire length of the ship. ~ 30%) is preferably provided.

  If the resistance and impact to the hull are large, the ride comfort will be bad, and the burden on the engine will be increased and the fuel efficiency will be adversely affected. Therefore, these adverse effects will be reduced by reducing the resistance and impact to the hull. The hull shape of the present invention that can be applied can be effectively applied to medium and small fishing boats and leisure-type boats.

The perspective view from the bottom face of the ship which has the hull shape of embodiment of this invention. Explanatory drawing which shows the shape of the concave curved surface of the 2nd bow part in the hull shape of embodiment of this invention. Sectional drawing in the 2nd bow part of the ship which has the hull shape of embodiment of this invention. The bottom view of the ship which has the hull shape of embodiment of this invention. The side view at the time of planing of the ship which has the hull shape of embodiment of this invention. Explanatory drawing which showed the slamming state of the ship which has the hull shape of embodiment of this invention. Explanatory drawing which showed the motion of the wave which flows through the side surface of the ship which has the hull shape of embodiment of this invention. Explanatory drawing which showed the motion of the wave which flows through the bottom face of the ship which has the hull shape of embodiment of this invention. Explanatory drawing which shows the shape of the concave curved surface of the 2nd bow part in the hull shape of other embodiment of this invention. The side view at the time of planing of the ship which has the conventional hull shape. Explanatory drawing which showed the slamming state of the ship which has the conventional hull shape.

Explanation of symbols

S1 Original ship
S2 Conventional ship
W1 Ship bottom skin width
W2 Bottom shell width of second bow
M1 1st water flow
M2 Second stream 1 Bow 2 Second bow 3 Projection bow 4 Ship side skin 5 Ship bottom skin 6 Keel 7 Stern 40 Lower ship side skin 41 Upper ship side skin

Claims (5)

The hull shape of small and medium sized boats is provided with a second bow to reduce wave resistance to the hull that is sailing behind the bow. It is assumed that a concave curved surface is formed in the part up to the vicinity of the line, and the width of the bottom shell plate is narrow in the concave curved surface forming part, and the second bow is 15% from the tip with respect to the total length of the ship. Hull shape characterized by being provided between -50% . The hull shape according to claim 1, wherein the second bow is formed from the vicinity of the upper edge of the left and right lower hull side outer plates. The hull shape according to claim 1, wherein the second bow is provided between 15% and 30% of the total length of the ship. The hull shape according to claim 1, wherein the concave curved surface forming portion has a shallow mortar shape. The hull shape according to claim 1, wherein a width of the bottom shell plate is narrow so that the concave curved surface forming portion has a substantially V-shaped cross section .